As a result, the thesis focuses only on the logistical issues of the horizontal and in-stop processes. The literature review shows that most of the previous work carried out in the field of transportation focused on the area of horizontal transportation with limited input for in-stop transportation systems.
Introduction
Motivation
However, just having the right mindset is not enough, as the actual transport systems must be efficiently planned and equipped with the appropriate machinery and technology. This document will also serve as a design guideline for mining engineers in the selection of conveyance systems applicable to ultra-deep gold mining environments.
Methodology
This thesis captures the current practices applied to the transportation of personnel, material and rock from the shaft station to the job site.
Background
Transportation needs analysis
One of the primary restrictions on mining at ultra-deep levels is the ventilation requirement. In order to maintain sufficient environmental conditions at acceptable levels, large amounts of air will have to be circulated, and the transports will therefore be large, with cross-sectional areas of the order of 20 m2.
Literature Review
General transportation issues
- Supply chain
- Management structure
- Communication and tracking
- System automation
Hattingh (1997) reported on the changes in the operational management structures of the Vaal Reefs Gold Mine. The system controlled a small fleet of automated trucks on the same roads as conventional machines.
Horizontal transportation
- Trackbound transport
- Monorails
- Conveyors
- Chairlifts
- Trackless vehicles
Guse and Weibezahn (1997) discussed the application and advantages of the monorail system in hard rock mines. Baker (1981) noted that replacing worn tires represented a significant portion of the operating costs of trackless vehicles.
In-stope transportation
With the changes that took place in the industry during the 1990s, interest in remote-controlled games declined. Recently, interest in remote-controlled games has been revived, with interest expanding to automatically controlled games.
Horizontal transportation
General transportation issues
- Mine planning and simulation
- Transportation management structure
- Communication
- Traffic control systems
- Automation
- Illumination of haulages
- Track work and track maintenance
The use of systems that monitor and control the ability of trains to enter designated areas by automatically stopping or derailing. the locomotive removes the human element from the control system. Figure 4-3 shows a generic horizontal 24-hour locomotive operating schedule for the transportation of personnel, material, and stone. The schedule shows: driver change, battery change and actual performance.
Personnel transportation
- Principles of personnel transportation
- Personnel loading bays
- Carriages
A brake system that acts on the wheels of the carriage and can be activated by the locomotive drive. During the transport of the shift, other tram activities are stopped and the transports are considered as a.
Material handling
- Principles of material handling
- Fit for purpose design
- Shaft Station
- Horizontal material transportation
- Cross cut
For effective and efficient handling of material carts at the shaft stations, the following measures should be considered. Support elements and other materials such as cement bags must be packed appropriately on the wagons and in accordance with the requirements of the stop panel.
Rock transportation
- Principle of ore transportation
- Ore tramming control and automation
- Orepass storage measurements
- Position monitoring
- Ore tracking
- Belt weighers
There are several areas where measurements could be made to provide useful information and help control ore transport. In order to move away from traditional methods, the miner interface will need to be removed. Some other useful measurements would be the locations of locomotives, hoppers, and other wagons, and monitoring the flow of ore through the mine's rock handling system.
Amounts of rock stored in any orepass or silo can be estimated from the top of the structure. The system has the potential to prevent gold-bearing ore from being transported to the wrong rockpass system (ie the waste passage).
Horizontal transportation audit
- Audit of trackbound transportation
- Overview
- Capacity
- Evaluation of trackbound transportation
- Cost implications
The impact of the rail-bound system on the underground environment will vary according to the type of locomotives used. Due to the tilting mechanism, the hoppers are not affected by the railway line. The weight of the hopper is disproportionate to the payload and the hoppers tend to leak at the door.
Similar to the drop bottom hopper, the gauge of the track affects the size of the ore that can be discharged. Due to the size of the hopper, the trackwork must be of high quality, requiring regular track maintenance.
Monorail systems
- Audit of monorail system
- Evaluation of monorail system
- Size
- Compatibility with other systems
The monorail's capacity to transport staff is limited by the length of train sets and the type of staff cars available. The monorail's primary role is to move heavy material and up to three material cars can be attached to a train. Due to the nature of cargo carriers, virtually all sizes and shapes of cargo can be transported.
Monorails can reach almost any part of the mine where there is a monorail track structure. Electric drive units are attached to a part of the track structure that is equipped with an electric power supply.
Conveyor belts
- Audit of conveyor belt system
- Powering systems
- Characterisation of Enclosed Belt Conveyors
- Evaluation of conveyor belt system
- Cost implications
Fines on the surface of the tire can also be deposited as the empty tire returns. Many of the problems associated with conveyor belts can be attributed to poor loading on the belt. Spreading the driving load along the length of the conveyor installation can reduce the tension in the belt.
Regular belt inspections are necessary to identify tears or damage to the belt in time. In addition, return shoes at the ends of the belt help prevent spillage.
Chairlifts
- Audit of chairlift system
- Overview
- Compatibility with other systems
- Evaluation of chairlift system
- Size
The load capacity of the chair lift is a function of the rope speed, the distance between the chairs and the distance between the supports. There must be special boarding and disembarking stations so that the chairs can match the rope speed. Electric or electro-hydraulic motors are the standard power sources for the pulley drive units.
The chairs are then held on to the rope by the friction between the rope and the support element. The drive and return wheels, as well as the intermediate support wheels, are designed with replaceable polyurethane inserts to minimize wear and tear on the rope.
Trackless Transportation
- Audit of trackless system
- Evaluation of trackless system
Installation costs are around R11 00 per meter for the rope, chairs and intermediate supports and an additional R240 000 for the power supply, return and. In an ultra-deep mine application, the ability to transport any vehicle without a shaft path imposes limitations on the size of the vehicles, so larger vehicles are not practical. Electric units use overhead power supply in the form of overhead overhead lines.
Such a maintenance philosophy includes systematically monitoring the engine oil for contaminants in the case of diesel vehicles and scheduling regular maintenance of the vehicles. Where diesel-powered vehicles are used, the ventilation during transport must be such that the exhaust gases are quickly removed from the environment.
Summary and conclusions
Monorail systems are versatile, run up steep grades and fit into small areas, but are slow moving and expensive to operate. Trackless vehicles are unsuitable as a means of transport in very deep level gold mines, as they are generally poorly exploited, require large excavations and are expensive to purchase and maintain. The work done prior to 1999 focused primarily on the stone handling aspects of the in-stope process with the aim of improving front feed and productivity.
Recent research initiatives have expanded the in-stope process to include personnel and material transport. The movement of personnel, material and rock must be integrated so that efficient intra-stop transport can be carried out efficiently.
In-stope transportation
Personnel
- Audit of in-stope personnel transportation
- Evaluation of in-stope personnel transportation
Vertical travel in the stope is accomplished through dip travelways, which are generally the original rise, or through travelways established adjacent to lift during the ledge of lift. Movement in the stope can be strenuous, as traffic routes are often blocked with equipment, material and ore (Figure 5-5). For example, dip and strike canyons, which are the main rock arteries, also serve as travel routes.
In-stop travel ways provide access to the work panels via dip and strike travel ways, which can be entered from either the top or the bottom of the stops. Routes are usually based on the mining layout, but they can also be developed as needed and are therefore flexible in terms of positioning.
Material handling
- Monowinch systems
- Audit of monowinch systems
- Monorail systems
- Evaluation of monowinch and monorail
The mono winch can be extended per stroke, allowing material to be supplied to the top of the plane or along the panel length. Although this system transports the material to the end of the chute, the material still must be moved from the chute to the point of application. Potentially, this system could extend the delivery point from the center of the rise to the end of the drain by using turntables at the drain position. At the middle intersection of the gutter/drain gully, the material can be guided to the gutter via the turntable.
Once operational in the strike channel, the monorail will be able to operate efficiently without disrupting the rest of the mining cycle. However, they are limited in that they have only recently been introduced to the reef horizon and only operate near the mid-elevation.
Rock handling
- Introduction
- Cleaning constraints
- Cleaning rates
- Face cleaning
- Strike gully cleaning
- Dip gully cleaning
- Sweeping and vamping
When positioning the last row of supports, the forward movement of the plane and the width of the shovel must be taken into account. Water jetting plays an important role in facial cleansing as it allows for a higher cleaning speed by moving the rock in the path of the scraper, thus reducing the number of rerigs involved in the cleansing process. The ability to remove the rock from the facade discharge point to the ore passage or immersion trench determines the length of the face panel and the progression of the face.
The scraper is further aided by the dive of the reef and often by the addition of another scoop. It is thus important that most of the ore is removed during the initial purification.
Guidelines
- Introduction
- Significant general findings
- Horizontal transportation
- General horizontal transportation issues
- Horizontal transportation of personnel
- Horizontal material transportation
- Horizontal rock transportation
- In-stope transportation
- In-stope personnel transportation
- In-stope material transportation
Transport systems must be prioritized to ensure fully reliable delivery, whether of personnel, material or stone. Train drivers must be highly skilled (trained) in the maintenance of locomotives, rolling stock and transport. Personnel loading bays, near workplaces, must be provided regularly, every 600 m to 800 m.
Crosscuts should be kept open for rock loading and other purposes (such as ventilation) at all times. For tonnages exceeding this figure, bypass rings or double transports should be considered.
